<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>
<p><h1>标签h1</h1></p>
<div  class="classB" class='classA' html='abc' class='[a?aa:bb,cc]'  style='width:100px'>我是div</div>
<div id="demo">
    <div  class="classB" class='classA' html='abc' :class='classC' :class='classD' style='width:100px'>我是div</div>
    <span>我是span</span>
    <!--我是注释标签-->
    <p><h1>标签h1</h1></p>
</div>
<style>
    .class-a {
        background: red;
    }

    .class-b {
        background: red;
    }
</style>
<script>


</script>

</body>
</html>